Cook the sushi rice according to the package instructions. While still warm, gently fold in the rice vinegar, sugar, and salt until dissolved. Spread the rice out to cool to room temperature.

Combine the soy sauce, lime juice, wasabi, and ginger paste in a bowl. Add the thinly sliced greater amberjack and toss gently to coat. Marinate in the refrigerator for 10–15 minutes.

Divide the cooled sushi rice evenly between two bowls.

Arrange the cucumber, cherry tomatoes, fresh coriander, and sliced green chili over the rice.

Top each bowl with the marinated greater amberjack, spooning over a little of the marinade.

Finish with a generous sprinkle of crispy fried onions and serve immediately.